Eliezer Golan, MD, Bruria Tal, PhD, Yossef Dror, PhD, Ze’ev Korzets, MBBS, Yaffa Vered, PhD, Eliyahu Weiss, MSc and Jacques Bernheim, MD
Background: Multiple factors are involved in the pathogenesis of hypertension in the obese individual.
Objective: To evaluate the role of a decrease in sympathetically mediated thermogenesis and the effect of the correlation between the plasma leptin and daily urinary nitric oxide levels on obesity-related hypertension.
Methods: We evaluated three groups: 25 obese hypertensive patients (age 45.7±1.37 years, body mass index 34.2±1.35 kg/m2, systolic/diastolic blood pressure 155±2.9/105±1.3, mean arterial pressure 122±1.50 mmHg); 21 obese normotensive patients (age 39.6±1.72, BMI 31.3±0.76, SBP/DBP 124±2.1/85.4±1.8, MAP 98.2±1.80); and 17 lean normotensive subjects (age 38.1±2.16, BMI 22.1±0.28, SBP/DBP 117±1.7/76.8±1.5, MAP 90.1±1.50). We determined basal resting metabolic rates, plasma insulin (radioimmunoassay), norepinephrine (high performance liquid chromatography) in all subjects. Thereafter, 14 obese hypertensives underwent a weight reduction diet. At weeks 6 (n=14) and 14 (n=10) of the diet the above determinations were repeated. Plasma leptin (enzyme-linked immunosorbent assay) and UNOx (spectrophotometry) were assayed in 17 obese hypertensives and 17 obese normotensives, and in 19 obese hypertensives versus 11 obese normotensives, respectively.
Results: Obese hypertensive patients had significantly higher basal RMR and plasma NE levels. Insulin levels were lower in the lean group, with no difference between the hypertensive and normotensive obese groups. At weeks 6 and 14, BMI was significantly lower, as were insulin and NE levels. RMR decreased to values of normotensive subjects. MAP normalized but remained significantly higher than that of obese normotensives. Leptin blood levels and the leptin/UNOx ratio were significantly higher in the obese hypertensive compared to the obese normotensive patients. Both these parameters were strongly correlated to BMI, MAP5, RMR, and plasma NE and insulin .Obese hypertensive patients excreted less urinary NO metabolites. A strong correlation was found between MAP and the leptin/UNOx ratio.
Conclusions: A reduction of sympathetically mediated thermogenesis, as reflected by RMR, results in normalization of obesity-related hypertension. In contrast, insulin does not seem to play a major role in the pathogenesis of hypertension associated with obesity. Increased leptin levels in conjunction with decreased NO production in the presence of enhanced sympathetic activity may contribute to blood pressure elevation in the obese.
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BMI = body mass index
SBP/DBP = systolic blood pressure/diastolic blood pressure
MAP = mean arterial pressure
UNOx = urinary nitric oxide
RMR – resting metabolic rate
NE = norepinephrine
Yoav Mattan, MD, Alice Dimant, MD, Rami Mosheiff, MD, Amos Peyser, MD, Steven Mendelson, MD and Meir Liebergall, MD
Background: Femoral hip fractures are a common occurrence in the elderly. Of the various fracture patterns, intertrochanteric injuries have the lowest rate of complications. Case reports of ensuing subcapital fracture have all been linked to incorrect placement of fixation devices or to osteomyelitis, while cases of avascular necrosis have only been reported rarely in the literature and are considered to occur at the rare rate of 0.8%.
Objectives: To check the incidence and outcome of AVN in intertrochanteric hip fractures.
Methods and Results: In a retrospective analysis of patients who had surgical treatment for intertrochanteric fractures, 10 patients (0.5%) underwent dynamic hip screw fixation for intertrochanteric fractures and subsequently developed painful AVN as their primary presentation. Three of these patients were also found to have subcapital fractures. On revision of the primary fixation no fault was found with nail placement.
Conclusions: The reported rate of AVN may be understated since many patients have limiting factors that prevent them from consulting a physician when in pain, and one-third of these patients die within 2 years. Therefore, we suggest that hip pain following fixation of an intertrochanteric fracture should prompt the clinician to consider the rare possibility of AVN or subcapital fracture.
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AV = avascular necrosis
Naomi B. Zak, PhD, Sagiv Shifman, MSc, Anne Shalom, PhD and Ariel Darvasi, PhD, MPH
The complex genetic nature of many common diseases makes the identification of the genes that predispose to these ailments a difficult task. In this review we discuss the elements that contribute to the complexity of polygenic diseases and describe an experimental strategy for disease-related gene discovery that attempts to overcome these factors. This strategy involves a population-based case-control paradigm and makes use of a highly informative, homogeneous founder population, many of whose members presently reside in Israel. The properties of single nucleotide polymorphisms, which are presently the markers of choice, are discussed, and the technologies that are currently available for SNP genotyping are briefly presented.
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SNP = single nucleotide polymorphism
Eduardo Garcua-Garcia, MD, Carlos A. Aguilar-Salinas, MD, Teresa Tusie-Luna, MD, PhD and Juan Antonio Rull-Rodrigo, MD
This review summarizes the clinical, metabolic and genetic characteristics of early-onset type 2 diabetes in Mexico. Early-onset type 2 diabetes is both a clinical challenge and a public health problem. It is calculated that almost 300,000 Mexican diabetics are diagnosed between the ages of 20 and 40. The large Mexican family structure and the high prevalence of the disease provide a unique opportunity to identify the genes and the metabolic abnormalities involved in this form of the disease. In a hospital-based population, our group found that insulin deficiency was the main defect in this form of diabetes. Mutations in the HNF-1α or HNF-4α genes or autoimmunity to the beta cell were found in a small proportion of cases, leaving unexplained the majority of cases. Also discussed are the epidemiologic and therapeutic implications of early-onset type 2 diabetes, and the possible role of genetic testing for prevention.
Ron Reshef, MD, Wisam Sbeit, MD and Jesse Lachter, MD
Ardon Rubinstein, MD and Elena Izkhakov, MD
Jacob Bickels, MD, Yehuda Kollender, MD and Isaac Meller, MD